Routine Name: randSymMat
Author: Brandon Furman
Language: C++
Description/Purpose: This function generates a symmetric matrix whose entries are random values between 0 and 1.
Input: This function accepts one integer as input. This integer designates both the number of columns and the number of rows.
Output: This function returns a symmetric matrix, in the form of an array2D object, whose entries have been set to random values between 0 and 1.
Usage/Example: Usage of this function is straightforward. The following code
int m,n;
array2D mat;
m = 2; n = 3;
mat = randSymMat(m,n);
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
std::cout << mat(i,j);
}
std::cout << std::endl;
}
outputs the following to the console:
0.00125126 0.563585 0.193304
0.563585 0.808741 0.585009
0.193304 0.585009 0.479873
Note that the entries are random, so these values may change upon running the code again.
Implementation/Code:
array2D randSymMat(int m) {
//Creates a new array2D object and
//allocates memory for it
array2D mat;
mat.allocateMem(m, m);
double tmp = 0.0;
//Loops through the lower triangular portion
//of the matrix and sets each element equal
//to a random number.
for (int i = 0; i < m; i++) {
for (int j = i; j < m; j++) {
tmp = (double)rand() / (double)RAND_MAX;
mat(i, j) = tmp;
mat(j, i) = tmp;
}
}
return mat;
}
Last Modified: February/2019